import java.util.Stack;

public class Test {
    public static void main(String[] args) {
        //Stack<Integer> stack=new Stack<>();
        Stack stack=new Stack();
        stack.push(1);
        stack.push(2);
        stack.push(3);

        System.out.println(stack.peek());
        System.out.println(stack.pop());
        System.out.println(stack.peek());
        System.out.println(stack.size());
        System.out.println(stack.empty());
    }
}
